A data signal may be transmitted and/or received along with an associated clock signal. The clock signal defines the bit-cell boundaries of the data signal and thereby allows a receiver to extract data from the data signal. The clock signal may be separate from the data signal or may be “embedded” within the data signal.
Clock signals may be controlled by clocking circuits that are associated with data-carrying communication links. A typical clocking circuit uses a local oscillator to generate clock signals that may be used to transmit and/or receive data. Frequencies of the generated clock signals may increase as data rates increase. For example, a 20 Gb/s/channel clock-and-data recovery circuit may require a local oscillator to generate clock signals of 10 GHz or more.
A local oscillator that is associated with a communication link is ideally capable of supporting any data rate that can be supported by the communication link and its associated transmitter and receiver. Some conventional local oscillator designs cannot efficiently achieve desired clock frequencies. For example, some of these designs occupy an unacceptable amount of die space when fabricated within an integrated circuit.